Oxygenation Dynamics

Question 1

Amount of minute ventilation and cardiac output

Answer 1

4-8L/min

Question 2

What type of blood gas is the first sign of shock

Answer 2

Uncompensated respiratory alkalosis. Body response to hypoxia is tachypnea.

Question 3

2 types of v/q mismatch and what types of patients for each

Answer 3

Venous admixture (Shunting): Capillary leak preventing o2 entering down into capillary bed where it can attach to hgb, pao2 falls (normal 80-100)
Deadspaceventilation: relate to blood flow…no perfusion. Pulm emboli, cardiogenic shock- LV weak

VENOUS ADMIXTURE:
COPD
Asthma
PNA
ARDS

Perfusion/ deadspace ventilation:
Trauma
Tension pneumo
Cardiac tamponade
Cardiogenic shock

Question 4

Importance of lactate

Answer 4

Lactate is an indicator of stress. Looked at by hour 1 of sepsis. Formed in both aerobic and anaerobic respiration. Product of glycolysis

Question 5

Oxygen Delivery Calc

Answer 5

DO2= Q X CaO2
Q= SV X HR
CaO2= [1.34 x hgb x (sao2)] + PaO2 X .003
1.34 x hgb x sao2 = o2 bout hgb (98%)
Pao2 x .003=0.006 dissolved o2 in plasma (2%)

Question 6

Hypoxic hypoxia

Answer 6

occurs when not enough oxygen enters the body, either because of low oxygen levels in the environment or because a medical condition reduces the ability of the lungs to take in oxygen.

Ex: environmental: climbing/flying high altitude
Medical: PE, ARDS

Question 7

Hypemic hypoxia

Answer 7

Blood can’t carry oxygen , due to hemorrhage, anemia or certain drugs, carbon monoxide (200x affinity w hgb than o2 with hgb aka binds w hgb shows sats 100% but really all hgb is bound w CO)

Tx: PRBC for anemia or 100% O2 for CO poisoning

Question 8

Stagnant hypoxia

Answer 8

Not enough blood flow to deliver O2

Any shock states, sickle cell, hypothermia (blood vessels constrict)

Question 9

Histotixic hypoxia

Answer 9

A result of poisoning or metabolic disorder, such as cyanide or alcohol

Most common is cyanide where cells are unable to use O2 (smoke inhalation)

Question 10

What has the largest impact on overall oxygen delivery?

Answer 10

Hemoglobin concentrations 

Question 11

3 Ps of EtCO2 (when etco2 low)

Answer 11

• Pulse- check pulse
• Perfusion- check MAP (>65)
• pH- partially compensated metabolic acidosis (your body becomes tachypneic to compensate for the acidosis- think dka- you want to protect their compensatory mechanism protecting their pH)

Question 12

Bohr Effect ***

Answer 12

Bohr- Body (tissues) Right

increased partial pressure of carbon dioxide (CO2) and decreased blood pH cause hemoglobin to have a lower affinity for oxygen, promoting the release of oxygen to the body’s tissues.

Hemoglobin’s oxygen binding affinity is inversely related to both acidity and carbon dioxide concentration. This describes a right shift on the oxy diss curve

Question 13

Oxy Hgb Curve

Answer 13

Right shift- Raised

Right shift = release (hemoglobin lets go of O₂ more easily → good for tissues that need oxygen).

Reduced affinity, increased temp, increased 2,3 DPG, inc H+, increased PaO2. Spo2 usually lower
your Hgb is not holding onto as much oxygen (bc it’s holding onto H+ and CO2 so no room for O2 to bond and also wants to offload their oxygen bc there’s no more room, more drop off)
Higher PaO2, lower SpO2

Left shift- Low

Left shift = lock (hemoglobin holds onto O₂ more tightly → not as much delivered to tissues).

Dec temp, dec 2,3 DPG, dec H+, CO
High affinity, all the hemoglobin is going to grab onto the oxygen but when it needs to release it, it won’t hgb doesn’t want to share its oxygen= higher spo2

Question 14

Haldane Effect

Answer 14

Haldane: Holding Lungs (left)

The effect of oxygen on CO2 and H+ binding to Hgb. As O2 binds with. Hgb it causes a state of cooperativity, causing a release of CO2 and. H+. Left Shift oxy hgb curve.

Promote CO2, unloading in the lungs

Question 15

Normal CO2 production amount

Answer 15

150L per day

Question 16

A multisystem’s trauma patient with massive hemorrhage has an ABG of pH 7.14 PaCO2 58, HCO3 18, PaI2 68, BE -9. What direction were the oxyhemoglobin curve move towards? 

Answer 16

Right
Higher acidosis
Hgb gives up oxygen more readily to the tissues

Question 17

A patient has an SPO2 of 87%. What would the approximate PaO2 be?

Answer 17

57mmHg

4-5-6-7-8-9 Rule
PaO2 40. SpO2 70%
PaO2 50 SpO2 80%
PaO2 60 SpO2 90%

Question 18

Oxygen delivery is a product of what

Answer 18

SAO2, Hgb, CO

Question 19

What causes a right shift on the oxyhemoglobin disassociation curve?
Alkalosis
Hyperthermia
Hypothermia
decreased levels of 2,3DPG?

Answer 19

Hyperthermia

Question 20

A shift to the left on the oxyhemoglobin dissociation curve results in impaired dissociation of oxygen from hemoglobin. What conditions would result in a left shift of the curve?
pH of 7.10
Temperature of 103
Decrease levels of 2,3DPG
PaCO2of 55 mm in mercury

Answer 20

Decrease levels of 2,3 DPG

Question 21

Possible TQ
How many ATP formed in aerobic respiration

Answer 21

36 ATP